Elevator signaling system



R H. GAYLORD ELEVATOR SIGNALING SYSTEM Filed May 20, 1925 4 Sheets-Sheet 1 INVENTOR.

0 N YS.

Dec. 22, 1931.

' n. H. GAYLORD ,837,215

ELEVATOR SIGNALING SYSTEM 4 Sheets-Sheet '2' Filed May 20, 1925 A TTORNEYS Dec. 22, 1931. 5, GAYLORD 1,837,215

ELEVATOR SIGNALING SYSTEM Filed May 20, 1925 4 Sheets-Sheet 3 ATTORNEYS.

Dec. 22, 1931. GAYLORD 1,837,215

ELEVATOR SIGNALING SYSTEM Filed May 20 1925 4 Sheets-Sheet 4 'lllllllml lull"! 1 4 /65 4 2 /04 A TTORNEYZS Patented Dec. 22, 1931 ROBERT H. GAYLORD, OF LOS ANGELES, CALIFORNIA ELEVATOR SIGNALING SYSTEM Application filed May 20,

This invention relates to an improvementin the type of elevator signaling system as described in the patent to James B. Smalley and Charles H. Reiners, No. 828,752, datezjl 5 July 2st, 1906. The main object of the invention is to provide selecting or intercontrolling means for both the signal circuits and the restoring circuits of a si naling system of this type so that only the first car of the installation to enter the signaling zone for a given floor will be enabled to cause operation of the signals and of the restoring means 'for that floor and direction of travel, to the exclusion of all other cars, thus preventing confusion in the signaling and also preventing a car which is not in control of the signal operation from operating the restoring n'ieans.

The feature of selection or intercontrol of the signal circuits and the means whereby such selection or intercontrol is accomplished are substantially the same as described in my patent application Ser. No. 700,604, liled March 20, 1924. The present invention contemplates the addition of certain devices to the system described in said patent application so as to selectively control the restoring circuits as well as the signal circuits and thus permit only the car which is in control of the signal circuits for a given floor to operate the corresponding restoring mechanism. In an elevator signal system provided with selective control means as described in said patent application, the first car of the installation which enters the zone for a certain floor at which a primary circuit closer or push button has been operated by an intending passenger assumes control of the signal circuits for that floor and direction of travel and causes its signals to be operated while preventing the operation of the signals for that floor and direction ct travel for any other car in the insta lation. lVi'th the system described in said patent application the restoriug circuits whereby the signals for a given floor are cancelled and the signal circuits rendered inoperative of the zone for that floor, are not selectively controlled but remain in condition to be operated by any car passing v out of such zone. As a result it is possible for a second car entering the signaling zone Serial No. 31,555

for a floor for which the signals are undercontrol of another car to pass through and out of said zone without the operator in said second car becoming aware that any signals are being given at that floor and to thus operate the restoring means to cancel the first cars sigl hile means are provided in each car whereby the operator may if he desires open nals.

a bi" il 1 passing out of said signaling zone, the opern his restoring circuit at the time of ator under the conditions above described, not being aware that another car was giving and receiving signals for that floor may pass out of the signaling zone without operation of the above described circuit opening means and thereby cause operation of the restoring means. This would cancel all of the signals ior that floor and render the circuits therefor inoperative, the disadvantages of which in certain instances are readily apparent.

The principal object of the present invention 18 to eliminate the possibility of any such operation of the restoring means by a. car

which so that when one car has assumed control of not in control of the signal circuits,

re signal circuits it alone will be capable of causing operation of the restoring means and the signals will therefore remain in operation until this car passes out of the zone regardless of the movement of the other cars.

Other objects and advantages of the invention will appear hereinafter.

The accompanying drawings illustrate embodiments of my invention and referring thereto:

Fig. 1 is a diagram showing the circuit connections and the selective control means for the signal circuits and for the restoring circuits for an elevator installation comprising two elevator cars. $9

Fig. 2 is a longitudinal view of a caroperated switch or commutator of the type shown in said patent to Smalley and Reiners. Fig. 3 1s a section on line 33 in Fig. 2.

4 is a section on line 44 in Fig. 2.

Fig. 5 is a section of line 5-5 in Fig. 9

E)- Fig. 6 is a side elevation of the selective control means for the signal circuits for one floor and direction of travel.

a side elevation of the main secsystem associated therewith.

be an electric lamp. Electrically operater all the cars for the Fig. 9 is aside elevation of a'inodi of selective control means for the si cuits and restoring circuits.

Fig. is a view similar to -F 8 hu't witt the type of selective control means shown in Fig. r p In Fig. 1 of the drawings .1 have iilutrated diagramn iatically the, various parts 01" a. signaling s'stem according my vention for an installation of two elevators indicated at 1 and 2. A suitable source of electricity for example an ordinary dynamo orgenerator is indicated at 5 although it Will of course be understood that it will no; in general-he necessary to provide a special source of electricity as the same may be obtained by connecting the operating circuits to the public power lines. Each elevator car is provided with an electrically operatedor controlled signal. 6 Which may forexample l or controlled signals may also be provided at the landings and adjacent the respective elevator shafts for signaling an intending passenger that a certain elevator car is approaching him in the direction which he desires to go. These signals are also preferably electric lamps and a series of the same, as indicated at 7 to 14:, are preferably provided for each elevator car in the installation. In Fig. i, the series of such signals nearest each elevator car corresponds to that car. The top and bottom floors are each provided with av single lamp for each ele ator and each'of the intermediate floors Wrh apair of lamps ioreacn elevator such as 8 and 9 for the second floor. These Will be usually located outsideof the elevator shaft adjacent to each elevator doorway as common at thepresent time, one or" said lamps at each floor serving to indicate the approach of a downwardly moving car and the other the approach of an upwardly moving car.

Suitable manually operated primary circuit closing means such as ordinary push buttons are alsoprovided at each floor by which the intendingpassenger by operating one of said circuit closing means will close or cause to be c os d b i f .i o o. rein in me s-gnai circuit 01 switch or commutator closes another brealz' inthe signal circults of the corresponding car for that floor and direction of travel the proper signals Will be operated. These manually operated circuit closing means at floor and direction of the landings are indicated at to 22 inclusive and constitute primary circuit closers, the top and bottom floors each being provided with one, and each intermediate floor being provided with two, of such primary circuit closers, the upper ones being to signal upvardly moving cars and the lower ones down- Wardiy moving as is customer in such devices. One side oi each of said manual circuitclosingmeansfiorexampie,one of the contacts of eac L on, in case such means are used, is inected to a suitable source of current, such as battery :24, and the other side of each of said manual circuit closing means is connected to a setting magnet adapted to control an electromagnetically operated circuit closing means corresponding to t floor and direction of travel, the circuit being completed from the other side of said setting magnet to the other side of battery 24 as hereinafter described. v hile only one set of push buttons is illustrated it Will be understood that any desired number of such sets may be provided, for example, in a large in stallation there may be two or more push buttons at each landing ioreaca direction of travel, arranged at convenient points adjacent the el va or siafts, all of said push buttons for one installation or one bank of elevator cars being crosscc inected injthe usual mann to the set-ting magnets for the same electro-magnetically controlled circuit closing means. These electro-magnetically controlled circuit closing means, indicated at 39 to 41 inclusive, constitute secondary circuit closers and Will be described more in detail hereinafter.

A car operated switching device or commutator is provided for ea h elevator car and is operated by connection With said car in any suitable manner, the construction and operation of said switches being substantially the same as the construction and operation of (-'fll'llllllililiiil'.i described in said Smalley d Pt-einers patent with the exception that tin". switches shown he 11 are adapted for a story or fivelent of sev lancrngs as shown in. said ley and Pteiners patent. The contacts and the electrical connections for the can, controlled switches are shown diagrannnatically i; Fig. 1 While the mechanical construction of such switches is shown more clearly respondingcar-controlledcommutator. Each of these commutators is adapted to determine the time when the signals for the correspondcars shall be operated, that is when the at the landing and in the car ll be 4 ted up provided that landing ."h button has been operated so as to close 'uer normally open break in the signal s. Each con'imutator consists of suitablelixed and relatively moving contacts and ng signal system Vinin the present embodiment the brushes are indicated as constituting the moving members thereof, said brushes being arranged in two groups corresponding respectively to up and down travel of the car and adapted to contact respectively and alternately with two correspondlng groups of fixed contacts arranged on opposite sides of the commutator. As shown in Figs. 2 to 5 each of said commuta-tors may comprise a moving member or brush carrier 26 adapted to be moved back and forth by operation of the corres onding car, said moving member for example comprising a nut 27 which is adapted to worl: on a screw shaft 28 operated by connection with the car operating means in any suitable manner. Suitable means are provided for tilting said moving member on said shaft at each end of its path so as to shift the brush carrier so that one group of brushes is operatively en gaged with the corresponding fixed contacts while the elevator car is travelling upwardly and the other group of brushes is operatively engaged with the other corresponding group of fixed contacts during the downward travel of the elevator car. Means for effecting this tilting operation may consist of a frictional bearing means as shown at 29 in Fig. 5 engaging screw shaft 28 whereby the nut 27 is caused to tend to turn or tilt one side or the other in correspondence with the direction of rotation of said screw shaft, and such means may further comprise a guide member 30 adapted to engage an arm 31 on nut 27 to hold the brush carrier tilted to one side while it is travelling in one direction and to the other side while it is travelling in the opposite direction all as set forth in the patent-to Smalley and Reiners above referred to.

The group of fixed contacts in each conmutator for the control of the down signals at the landings comprise two series of contact plates, one of such series being indicated at 33 to 35 inclusive and the other series being indicated at 36 to 38 inclusive. These two series of contacts are adapted to be engaged by the brushes as the car moves downwardly and it will be observed that each plate of the series 33 to 35 is connected to a down light; that is, contact plate 33 is connected to lamp 8, contact 34 to lamp 10, etc.

Contact plates 36 to 38 are connected to the correspondingelectromagnetically controlled switches or secondary circuit closing means indicated as mercury pots 39 to 41 for control of the down signal circuits, each of which is provided with pivoted contact arm 42. Each of said connections from the contacts of the car operated switch to the mercury pots includes or passes through the corresponding selecting or intercontrolling devices hereinafter described. Said pivoted arms 42 for the mercury pots are operated by setting magnets 43 to 45 inclusive which are connected to and'controlled by the respective down push buttons or primary circuit closers 16, 18, and 20. The pivoted contact arms are all electrically connected to one side of the dynamo or source of current 5. r.

The construction and arrangement of the mercury pots 39 to 41 together with the setting and restoring magnets for controlling the operation of the pivoted circuitclosing arms 42 is shown in Figs. 7 and 8. Each setting magnet has an armature 46 adapted to control said contact arm 42. Said arm is normally held out of contact with the mercury in the mercury pot as shown in Fig. 7 by engagement of armature 46 with the other end of said arm as at 47 thereby causing a break in the signal circuits for the corresponding floor and direction of travel at this point. Upon energization of the setting magnet due to closing of the circuit at the corresponding push button, armature 46 will be attracted and contact arm 42 thereby released, permitting said arm to fall into the mercury pot and make contact with the mercury therein so as to close the circuit at this point. There is provided a restoring magnet as indicated at 4-8 to 50 for each of the contact arms 42 for restoring the same to the normal position as shown in Fig. 7 as the car starts to move away from the floor for which the signal has been operated, as will be described more in detail hereinafter.

It will be seen therefore that each intermediate fioor, for the downward travel of the car, is served by one of said floor signal lamps such as 8, a contact plate of the caroperated switch such as 33 connected therewith, a contact plate such as 36 adapted to be electrically connected to said first-named plate as hereinafter described, said latter contact being connected to the source of elec trical supply through an electromagnetically controlled switch means or secondary circuit closer such as 39 adapted to be operated by operation of a push button or primary circuit closer at the corresponding landing, and also through selecting or intercontrolling means for the signal circuits and for the restoring means, which will be described more in detail hereinafter. In order to control electrical connection between contact plates 33 and 36, 34, and 37, etc, there is provided a brush or brushes for each series of plates, as indicated at 51 and 52, these brushes being electrically connected as indicated. It will be obvious that when any one pair of these brushes engage the respective contact plates, for ex-- ample contact plates 33 and 36 the corresponding floor lamp such as lamp 8 will be lighted up providing the other breaks in the circuit are closed. It is preferred to provide several pairs of these brushes 51 and 52 and space the pairs a distance apart less than the width of any single plate of the series so that each pair of corresponding plates such as 33 and 36 will be electrically connected while the car is moving for several floors so that the floor light. will light up several floors in advance of the cars and will remain lighted until the car reaches the floor, this arrange- ,ment of the brushes being shown diagrammatically in Fig. 1 and being also shown in Be r a The car signal circuits are also controlled by contact means in the car-operated commutator, comprising for example a long contact strip 54, electrically connected to the car signal. in the correspondingcar and thence to the source of electric power. There is pro- 7 vided one or more pairs of brushes 56 and 57,

said brushes being electrically connected togetlier and the brushes 56 being adapted to make contact with contact strip 54 and brushes 57 being adapted to make contact with the series of contacts 36 to 38. It is preferred to provide contact strip 54 and brushes 56 rather than to attach thecircuit from the car lamp directly to brushes 57 but Y thisconstruction may not be necessary in all cases. The car signal is therefore in circuit 1 1 rwith orush means, such as brushes 5( adapted the series of contacts to 38. In embodiment these brushes 57 are from the brushes and 52 aforesaid and this is the construchat preferred but it will be observed as shown in Fig. 1 that when these brushes are in the position shown in that figure, one brush 57 rests on the same contact plate as a brush 52 and at that time said brushes are in effeet a single brush. One purpose of separating said brushes however is to provide different periods of advance operation of the landing signals and car signals. For example in order to light up the our light only a floor or so before the car reaches the floor, brushes 56 and 57 are located behind-the fore- .most brushes 51 and 52 so that the car light which the signals have been operated, such ion of the circuits to normal condior accomplished in this instance by the secondary circuit closer, that is,

r ,tora

out of its mercury pot such as 39. Such restoring means may comprise the restoring ma nets 4.8 to aforesaid, of which magnet r .i energized (subject to certain other conditionsas .liereinafter described), attract armature means 149 on contact arm 42 and by rais rig the corresponding contactarm 42 in Fig. 7. Said electromagnet i8" lift said arm out of the mercury pot .39 and cause the other end of said contact arm to be again brought underneath the end of, armature 48 where it will be helduntil the setting magnet 43 is againenergized. In order to energize the restoring magnets at the proper time th re are provided a series of contacts 58 to 60 upon the car-operated switch or commutator. Brush 61 is adapted to engage said contacts and is connected in any suitable manner to battery 24 for example as shown by electrically connected to a brush 8 engaging con tstrip 63 which is elecly connected to said battery. The respective contact plates 58 to 60 are so positioned that when the car starts to move away from an floor at which the si nals for that car have been operated, brush 61 will engage the corresponding one of said contacts'and energize the corresponding restoring magnet so as to break thesignal circuits at the sec ondary circuit closer as aboveset forth, such opening of the secondary circuit closer being azso dependent according to my invention on certain other conditions as hereinafter described. V V

The brrsiies above mentioned have been shown in Fig. l in the relative positions they occupy as car 1 is descending these brushes therefore controlling the car signal to said car during downwardly travel and the down signals at the landings for that car. The brushes are omitted from that part of the commutator of car 1 in Fig. 1 corresponding to the upward travel of the car, as such brushes are not in operative position at this time, being out of operative contact with the up plates on that sideof the commutator. Contact plates and strips 65 to are also provided however at the other side of the caroperated switch and are connected in the circuits and adapted to function during upward travel of the car in the same manner as the above described contacts function in the down ward motion of the car. 'When the car rooves upwardly the brushes forthe up COIIiZtcb plates are shifted intoisuch position by means operated by the car as shown in said Smalley and Reiners ipatent, so as to bring such brushes into position to engage the up contact plates'65 to 75and thus control the up signals and the corresponding restoring magnets. Thisshifting of the brushes will be referred to hereinafter. The brushes for the up? contact plates are similarly but oppositely arranged to those above described for the down contact plates. Said upfibrushes are indicated at 87 to 92 in Fig. 3 in inoperative position during downward movement of the car, said brushes.

being inoperative because of thefact that each connected pan of brushes such as 87 and 88, engage only one series of contactplates,

' such as'the series 68 to 70. Mercury pots or secondary c rcuit closers 76 r to T8. setting magnets 7 9 to 81 and restoring magnets 82 to 84 are also provided for controlling the up signal circuits, all of said means being connected and adapted to function in a similar {manner to those above set forth for the down signal circuits. The system is therefore provided with similar control means for upwardly and downwardly movement of the cars. It will also be understood that the car-controlled switching means for push-button only when said switch is open,

for example, at night.

The above description of the signal system applies to all intermediate floors but in order to provide for operation of the signals at :7, the top and bottom floors at the proper time it will be observed that the commutator contacts corresponding to each down signal at the top floor are located in the same series as those for the up signals for intermediate :zrffioors, while those for each up signal for the bottom floor are grouped with those for the down signals at intermediae floors. It will also be observed that in the normal operation of the elevators there is no need in 3:5 the case of the top and bottom floors of the manually operated primary circuit closers nor of the electromagnetically operated secondary circuit closers controlled thereby. There are therefore no mercury pots for the is'gnals atthese floors nor any setting and restoring magnets nor restoring contact plates in the car-operated switches, such signals being adapted to always operate when a T211 enters the signal zone, subject however to 4.1 theselecting or intercontrolling means hereinafter described. Push buttons and 22 are however provided at the bottom and top floors respectively and are connected preferably through suitable resistance 93 to battery These push buttons normally have no funct'on but when the elevators are not in normal operation, for example, at night, switch 86 may be opened and, in such case, closing of any push button, including 15 and 2223 will. cause bell S5 to ring. These special provisions are also substantially the same as in the said Smallev and Reiners patent.

My invention comprises in connection with the above described signaling system, elec trically operated selecting or intercontrolling means which are incorporated in the connections for the floor landing signals and car signals and preferably between the car-operated switches and the mercury pots or secondarycircuit closers. A form of electromagnetic selective control means for the signal circuits is shown in detail in Figs. 6 and 8. There is provided a set or series of such intel-controlling means for each floor and direction of travel and each set or series comprises a plurality of controlling electromagnets, there being one of such controlling electromagnets in each series for each elevator car in the installation. In Figs. 6 and 8 is shown a set of such devices comprising two control ing electromagncts 101 and 102 corresponding to the two elevator cars 1 and 2 in the above described installation. Said e'ectroinagnets are shown as mounted adjacent one another but this is not necessary since there no mechanical interconnection between such devices, the same being connected only electrically, so that they may if desired be remotely separated from one another. In fact each of the electromagnetic devices 101 and 102 may be mounted adjacent the corresponding car-operated switch, and under certain conditions this method of installation may be advantageous. Each electromagnet controls an armature 100 carried by or attached to a pivoted arm 99 controlling a circu t breaker or controller. For this purpose said arm 99 may cooperate for example with a mercury pot 103 to control a branch circuit included in the car and landing signal circuits for the corresponding elevator car, as hereinafter described. Each clectromagnet 101 and 102 may comprise two coils or windings 104 and 105 which in the form shown in Figs. 6 and 8 are wound on the same core and are connected in such a manner that when energized they act in opposition. In practice the two windings may be arranged as shown, or they may, if desired, each extend substantially the entire length. of the electroinagnet. The series of selecting devices shown at the left in Fig. 1 are for controlling the up signal circuits and those at the right for the down signal circuits, there being a set of such devices for the up signals for each floor except the top floor and a set of devices for the down signals for each floor except the bottom floor. Because of the arrangement of the contact plates in the car-operated switches as above set forth the set of intercontrolling devices for the down signals at the top floor are grouped in the diagram with the intercontrolling devices for the up signals at the intermediate floors and. similarly the intercontrolling devices for the up signals at the bottom floor are grouped with the devices for the down signals at the intermediate floors- The coils or windings 104 for all the electromagnets of a given set are connected in series. for example by wires 107. A connection 106 leads from one of said. coils to suitable electrically operated holding means such as electromagnet 142 adapted to control the restoration of the secondarv circuit closer to normal position as hereinafter described, said electromagnet 142 being in turn Connected by wire 113, to the corresponding mercury pot or secondary circuit closer of the series 39 to 41 or '76 to 7 8, and connections 108 lead from thewinding 104 of the electromagnet at the other end of the set to the several windings 105 of all the electromagnets in that set in parallel or multiple connection. From each coil or winding 105 a connection 100 leads to the corresponding, pivoted arm 99 which establishes a contact with mercury pot 103 from which a wire 110 leads to the corresponding contact :;of the series 36 to 38 or 68 to 70 of the corresponding car-controlled switch. I Each of the secondary circuit-closers 39 to 41 and 7 6 to 7 8 may be provided according to my present invention with one of the above mentioned holding means 142, which may comprise an electromagnet located'beneath the arm42 of said circuit-closer and at the other side ofthe pivoted support of said arm from the corresponding restoring magnet 41 such as 48, as shown in Figs. 7 and'8. The position of such electromagnet 142 is suc that ar. 1 42 when lowered to closed position, as in Fig.8, rests upon the core 143 of said. magnet, so thatwhen said magnet is eneragi zed it holds said a in firmly in closed positionand prevents it being opened by the restoring magnet until the holding magnet is dc-energized. l have found it advantageous to separate the iron bracket 144 supporting the detent magnet 142 from the iron bracket 145 supporting the restoring magnet such as 48 by a layer orblocl: of non-magnetic material, such asbrass as indicated at 146, so as to prevent leakage of magnetic flux from magnet 48 through bracket 144, thus permitting the attraction of ma net 48 to act on arm .7 42 only on the properside of the'pivotal support thereof. It will be observed, Fig.8, that theholding magnet 142 is connected in all or the signal circuits for th corresponding floor and is therefore adapted to b'e-energized whenever any signal for that floor is in operation.

1 also prefer to provide in connection with the above described system a car-operators switch lll'in each elevator for cancelling or controlling the landing and car signals for that car and a car-operators switch 112 for controlling the restoring circuits for that car, 'each of the elevator cars 1 and 2 being provided'with one of each of these switches.

The signal circuits are as follows. From the dynamo 5 a wire 115 leads to branch wires 7 116 and 117, wires 116 being connected to the contact arms 42 of the secondary circuit closers for the down signal circuits and wire 117 being connected to contact arms 42 for the up signal circuits. From each mercury pot or from the other side of each secondary circuit closer a wire 113 leads to the corresponding holding magnet 142. From the other end 01 said magnet a wire 106 leads to the correspondingsetof selecting orintercontrolling electromagnets as above described and from each mercury pot 103 of each of said sets a wire 110 aforesaid leads to the proper con- 36 to 38 or 68 to 70 atthe correspondcaroperated switch. From the contacts "3 of the series to 85 and to 67 of each carthe car operated switch, wires 123 and 124 lead to the car signal 6 in the corresponding car, the other side of said car signal being connected, to ether with wire 121, to the caroperators control switch 111. t Wlll be seen therefore that by operating said control or s gnal-cancelling switch the return circuit for l A- e car signal and landing signals is interrupted. V

The primary or manual control circuit leads by v. e 126 connected to one side of battery 24 an d wires 12? and 128 respectivelyto the setting magnets 43' to 45 and 7 9 to 81,

from which wires 1 9 lead to the corresponding irimary circuit closers or push buttons .6 re 21. The return ci suit for said circuit closers is established by connections130 and 1.31 to the otherside of the battery 24. 7

The restoring circuit also leads by connection 126 and connections 12'? and 128 to the restoring magnets 48 to 50 and 82 to 84, thence by wires 132 to the respective restoring circuit contacts 58to 60 and 72 to 74 for allt-he car-operated switches in parallel, and from the long contact strips 63 and 75 of each car operated switch by wire 133 to the restoring circuit switch 112 in the corresponding car. From said switches return wires 134 lead to the other side of battery 24. Opening of the restoring circuit switch 112 in any cartheretore serves to open a break in all of the restoring circuits corresponding to that car so that such ca in passiug out of the signaling zone for any tloorwill not cause the restoring magnet to be energized and will therefore permit the c responding secondary circuit closing mean r mercury cup such as 39 to remain in closed or operative posltion.

The operation of the above described signaling system is as follows:

In normal or inactive condition assuming that none or" the primary circuit closers or. push buttons 15 to 22 at'the landingshave been operated by an intending passenger, the

secondary circuit closers are all in open' posimeans as above describer tion as in 7, that is to say the contact arms 42 for all the mercury cups 39 to ll and T6 to 78 are held out of contact therewith as above described. The respective intercont-rolling electrxi-magnets 101 and 1.02 are therefore dcenergized and the armatures 100 thereof allow the contact arms 99 to rest in the mercury cups 103 and close the connection at this point, so that in normal condition all of the circ i controllers or circuit opening devices of the selecting intercontrolling means are in closed position. The signal circuits are not, however, completed since the complete establishment of any signal circuit depends not only upon the closure of the corresponding contact arm 99 and mercury rup 103 of the intercontrelling means but also upon the closure of the circuit at the main secondary circuit closer or mercury cup of the series o9 to ll and '76 to 78 and also upon closure of a connection between the corresponding contacts of the car-operated switch.

Assuming that an intending passenger operates one of the push buttons, for example, the down push button 16 at the second floor, the corresponding control circuit as above described will be completed and the corresponding setting '1 iagnet 43 will therefore be energized, causing the corresponding contact arm 12 to drop into mercury cup 39 as shown in Fig. 1 and in Fig. 8 and close connection at the secondary circuit closer for the down signal circuits for the second iioor for all the cars. The first descending car which enters the signaling zone for that floor, for e car 1 will. then cause the break in the s switch to be closed by operation of the hr in. The break in the landing signal circuit will be closed first, by engagement of a pair of brushes 51 and with contact plates 3 and 36 thus completing the signal circuit through the down landing signal 8 at the second floor for car 1. Current will then pass from dynamo 5 through wires 115 and 116 to contact arm 42 and mercury cup 39, thence by wire 113 to holding magnet 142, and through Wire 106 to the set of selecting or intercontrclling means corresponding to the down signals for the second floor. The electric current passes first in series by connections 107 through the coils or windings 104 of all the electromagncts 101 and 102 of that set and then passes through connection 108 to the other winding 105 of the electromagnet 101 corresponding to car 1. From said winding 105 the current passes through the corresponding connect-ion 1.09 to contact arm 99 and mercury cup 103 and thence by the corresponding wire 110 to the down contact 36 for the second floor of the car-controlled switch corresponding to car 1. Since the circuit is closed at this point by brush means 51 and 52 in said caroperated switch current will then flow through said brushes to contact plate 33 and thence to the corresponding down landing signal 8 at the second fioor and through wires 120 and 121, switch 111, and wire 122, back to the dynamo 5. Since the two windings and 105 of each electromagnetic controlling device are wound so as to oppose each other upon energization thereof, the armature 100 of magnet 101 corresponding to car 1 remains unaffected because both windings hereof are energized, and the contact between means 99 and 103 of such device therefore remains closed. The down signal lamp 8 at the second floor will therefore be lighted up, signifying to the intending passenger that car 1 is approaching that floor. In the case of the other electromagnetic intercontrol device or devices such as 102 of the same set however only the coil 10% is energized, there being no connection established to the coil 105 of said device, so that the armature 100 thereof is attracted and the corresponding circuit is interrupted by breaking the connection between members 99 and 103 as indicated at 140 in Figs. 1, 6 and 8. An additional break is therefore established in the circuits of the down landing signals at the second floor for all the other cars except that which has assumed control of the signals so that no down landing signal at the second floor for any other car can be operated as long as said first car remains in control of the signals, eventhough such other car comes within the signaling zone for that floor and thus causes the break in the circuit at the corresponding car-operated switch to be closed. It will be seen therefore that in any set of selecting or intercontrolling devices the first device to operate, that is to say the first device through whose contact means 99 and 103 the current actually flows, remains in operative position and retains the connection closed at this point while opening such connection for all the other devices associated therewith and thereby rendering inoperative the signal circuits for the other cars for that floor and direction of travel.

As car i approaches closer to the second floor, say when it is one floor or so away, a pair of brushes and will operate to close the circuit between contact strip 5st and contact plate 30 of the correspondin car-operated switch. Contact plate being then in electrical connection with the dynamo through the secondary circuit closing means and the inter-controlling device as above described, current will flow through brushes 5? and 56, contact strip and wires 123 and 12% to the car lamp 0 in car 1 and thence through switch 111 and wire 122 back to dynamo 5. Car signal lamp 6 is thus illuminated, signifying to the operator of car 1 that he is to stop at the second floor. Thus both the landing and car signals corresponding to car 1 are operated wli e both of said uignals for all other cars in the inst llation, such as car2, arerendercd mo .e h e by reason of a break in the circuits 1- Whichthey occupy when s ch si ing controlled by car 1 as alio e descrihc will be seen is the operat' cuits includeflthe holding 'net isassociated with he corlesponding secondary cire cuit closero ry cup 30 and that 533 as long as c; of signals, the arm i2 of closer will therefore to h oven thong i c zone" for in direction cuit at tlz fective in opening the ..y it. it closer because of the holding QuGCtOf holding magnet 142.! 1 1e: our in the tem may therefore rough and out oi. the Zone without cauiingo ieration oi? the restoring 'nieans. ll hen car about to leave this signaling" zone and ('32 come into position Ssoas to close the Conn spending restoring circcnl. a

t 1g ma net Such coin;

S'oOl' restoring circuits is at operating the restoring means the reason above described. The trolling the connections a the switch in the signaling storing circuits are so that the connection is o: I signal circuit segmentssome the connection is competed in i, circuit." Thus it wi he soon brushes in the posilons shown in connection is already completed storing circuit but I ll in the signal circuits so that in operation and the vented from operatir travel of the brushes sented as downward as dicated adjacent brushes and 5?. in last of the pairs of brushes 51 and incl 57 pass out of engagement ar-operated in the re-' i 1 illFx is preing magnet lo responding segments however the signal cir cuits will be interrupted and holding magnet 142 will be de-energized. Since the restorener ized con at LillS time is dition the restoring means will be immei iately operated to break the connection the secondary circuit closer. It will he observed hat as soon as the signal circuits for car I are interrupted the circuit closing arm 99 of the intercontrolling devices for the othe cars will be caused to drop and reestablish coniection with the corresponding mercury cups 03, and if a connection should established in this manner in the signal circuits for another car which was then in that Zone before the circuit is broken at the secondary circuit closer as above described it will be seen that the s1 'nal circuits would he esta 1: L J 1 l ii ned for Sfilfi other car and toe .ioiding magnet 142 re-encrgized and operation of the rest ring means prevented. Such a contino "3 7: 1- in- 7-b "t {3131 eiic is LIQJILeGC iowei or y me ac 1311 -l e 42 t l t 1 t' i. it motion or or iii to L11 ea l he coiinec ion at the secondary circuit closer takes place much more rapidly than the motion of arm 99 to close connection at the intercontrolling means, since arm 42 is moved by the magnetic attraction of the restoring magnet e8 while the arm 99 is moved to closed position only by I gravity; Furthermore, magnet 48 is already i with cancellation of the Further more the intercontrolling devices are at the time restored to normal the entire system for that Zone is thus restored to its original condition. V

The operator of any car may, upon receiving: a gnal to at a certain floor, but not wanting to stop in answer to this signal, transferthe control of the signals for that floor to the next car by opening the signal circuit transfer switch 111 in h s car. Not only the signal in such first car, but also the corresponding landing signal, will thus be canceled, and the intercontrolling means will all be restored to normal conditionand the holding magnet 142 will be die-energized,

while the contact will remain closed at the main secondary circuit closer for that floor,

- so that the next car to enter that signalnig Zone or any other car then in such zone will assume control of the signal circuits-and will also assumecontrol of the restoring means due to re-energizationof holding magnet 142 upon such reestablishing of the signal circuits. The operator may, on the other hand,

sition and,

open said transfer switch 111 at any time before or during the passage of his car through the signaling zone of a floor at which he does not wish to stop, before receiving a signal to stop at that floor, and in that case his car will be prevented from establishing any signal circuits for that floor. Or, the operator after having stopped at a floor in response to a signal, may find that he cannot take on all the waiting passengers. and in'this case also he may open switch 111 and transfer the signals to the next car so that such next car will also stop at that floor.

It should be noted, however. that opening of switch 111 alone in any car does not interrupt the corresponding restoring circuit so that if this switch alone were opened such car would cause operation of the restoring means upon leaving the signaling zone for that floor, provided no other car had yet entered that zone and assumed control of the signal and restoring circuits, and would thus prevent the next car from receiving and giving the signals in the desired manner. It is therefore desirable to provide another transfer or control switch 112 in each car and included in the restoring circuits as above described, so that the operator may, when opening switch 111 for any of the above reasons, also open switch 112 and thereby open his restoring circuits and thus prevent operation I of the restoring means when his car passes out of the zone. This ensures that the system will be left in proper condition so that the next car to enter that signaling zone will assume control of the signals. Since it is generally desirable to open both of said transfer switches at the same time, I prefer in general to form said switches as a double-pole switch, so that a single operation serves to open or close both the signal circuits and the restoring circuits simultaneously. Improper operation of the restoring means by a car which has released control of the signal circui ts is thereby prevented.

The control of the restoring circuits so as to prevent operation of the restoring means by any car which is not in control of the signal circuits may be accomplished in other ways than that above described although such method is very advantageous for this purpose from the standpoint of simplicity and positiveness of operation. For example, the apparatus shown in Figs. 9 and 10 is adapted to control the restoring circuits in a similar manner. In Fig. 10 I have shown diagrammatically the parts of the system and the circuits for only one floor and direction of travel, for example for the down signals for the second floor. It will be understood however that the system is in this case provided with car-controlled switches adapted to control connections in the signal circuits and having contact segments as above described correspondingto the different floors and direction of travel, such contacts for the second floor down and the contact strips cooperating therewith being indicated at 33, 54, 58, and 63. Said car-controlled switches are also provided with brushes 51, 52, 56, 57, 61, and 62 adapted to control the connections between said contact segments and strips and thus control the signal and restoring circuits as above described. The system further comprises elevator cars 1 and 2, electric dynamo or other source of electric power 5, car signals 6, landing signals such as 8, push buttons or primary circuit closers at the landings, such as 16, a battery or other source of electric power 24, and secondary circuit closers on mercury cups such as 39. Each of said mercury cups is provided with contact arm 42 and the connection between said mercury cup and said contact arm is controlled by setting magnet such as 43 and restoring magnet such as 48 as above described.

The intercontrol means used in this case are of somewhat different construction than above described and are adapted to directly control circuit connections not only in the corresponding signal circuits but also in the corresponding restoring circuits. For example each of the intercontrolling devices 101 and 102 may comprise two separate and opposing electromagnets 104 and 105. Each of said devices is further provided with a mercury cup 103 and contact arm 99, adapted to control a connection in the corresponding signal circuits, said arm being pivotally mounted at 150 so that gravity holds the arm normally down in closed position within mercury cup .103. Said contact arm 99 is provided with armature means 100 between the two electromagnets 104 and 105 and adapted to be attracted in opposite directions upon energization of one or the other of said magnets. Each intercontrol device also comprises another circuit closed such as mercury cup 151 and contact arm 152. Said contact arm is pivotally mounted at 153 and is provided with counter-weight means 154 to normally hold said arm in open position. Contact arm 152 is also provided with armature means 155 adapted to be attracted by electromagnet 105 upon energization thereof so as to move said contact arm to make contact with the mercury in mercury cup 151. In Fig. 9 the intercontrol devices for both the elevator cars are shown in normal position with the connection closed in the signal circuit and 'open in the restoring circuit. The system further comprises electrical connections 115, 106,107,108, 109,110,119,120, 121, 122, 123, 124, 126, 127, 129, 130, and 131 substantially as above described with the exception that wire 106 leads directly from the secondary circuit closer 39 to the intercontrol means, instead of through the holding magnet which is eliminated in this case. It will therefore be seen that all the electromagnets 104 of the intercontrol devices of each setare connected in series while the electromagnets 105 of such devices are connected inparallel substantially as 1nthe first described form the invention. The restoring circuitis some:

responding mercury cups" 151 to the corresponding restoring c1rc'u1t contact segments such as 58 at the car operated switches,'and return wires 158 leading from the long contract strips 53 of the car-operated switches back'to. battery 241 It is therefore evident that when the contact arms 152 are in normal or open position as shown in Fig. 9-the corresponding restoring 'circuit is broi-zen at this point and can only be established upon energizationof the corresponding velectromagnet 105. g I also prefer to provide in this form of the invention a transfer switch 111 in each car andincluded inthe corresponding signal circuits in the same manner and for the same purposes as above described, but as will appear hereinafter it is unnecessary in this form of the invention to provid any transfer switch in the cars and incl in the restoring circuits, since the completion of any restoring circuit depends directly ded uponcthe completion of the corresponding closer 39 through wire 106 and then through i all the electromagnets 104: of the correspondsignal circuit so that opening of the signal circuit transfer switch 111 will ensurethe opening or the remaining open of'thecon nection between circuit closing members 152 and 151 in the corresponding restoring cir-' cuit. 1 i Y The operation of this form of the invention is as follows: I 7' Assuming as before that an intending passenger has operated push button 16 at the second floor and for adownwardly moving car, setting magnet 43 is thereby energized and closes connection atthe main secondary circuit closer 39. If now car 1 enters the signaling zone for the second floor down, the signal circuits will be completed first for the landing signals by means of brushes 51 and 52 and then for the car signal by means of brushes 56 and 57 so that both of said signals willbe'operated. lhe operation of the intercontrolling means upon completion of the i signal circuits in thislmanner isas-fol ows:

Current passes from the'secondary circuit ing set inseries and then through electromagnet 105 of the intercontrol device 101 cor-- responding to car 1. From here the circuit is completed as before through contact arm 99', mercury cup 103 and wire 110 to the con tact 36 of the car-operated switch forvcar l,

and hence throughthe car and landing sig- 7 energized and since said electromagnetsoppose each other the armature 100 is attracted equally in both directions and contact arm 99 still remains in closed position due to gravity. In the ntercontrol device 102 on the other hand only the electromagnet 104 is energized,

which therefore attracts armature 100 and moves contactarm 99' to open position, so as to break the connectionin the signal circuits for the other car at this point. The operation of the intercontrol means as regards the signal circuits is therefore substantially the same as in the form first-described. At the same time however 'energization of the electromagnet 105 of the intercontrol device 101 attracts armature 155 of contact arm 152 and throws said arm to closed position in mercury cup "151 so as to close a connection in the corresponding restoring circuit. Since the electromagnet'105 of the other intercontrol device or devices such as 102 in that set remains unenergized however, contact arm 152 ofV-such 7 other device ordevices remains in open position so that none of the restoring circuits for the other cars can be completed. Itis'therefore evident that only car 1 can effect operalilOIl'Of the restoring means as long as itis in control of the signal circuits,'-e ven though another car, such as 2, should pass through and out of this signaling zone and thereby close its connectionin the restoring circuit at the car-operatedswitch; Y

The restoring operation is in this case effected-as soon as brush 61 comes into contactwith segments 58 and thereby completes the restoring circuit through Wires 126, 127, restoring magnet 48, wire 156, contact members 152 and 1510f the intercontrol device 101, wire 157, contact segment 58,;brushes' 61 and 62, contact strip 63, and wire 158 back to the battery24l It should be noted that in this case the restoring operation should take place while brushes 51, 52, and 57 are stillinen gagement with contact segments 33 and since the restoring circuit can onlybe completed while the signal circuit remains established. For this reason it is essential that brushes 61 and 62 should be so positioned relative to the other brushes that the connection is closed with contact segment 58 before the connection is broken by the Contact segments 33 and 36. Itm'ay be pointed outas an advantage of this form ofthe'invention that the actual breaking of the circuit during the restoringoperation takes place in every case at the main mercury pot or. secondary circuit closersuchas 9 instead of betwee the brushes and'contact segmentsof the cari cribed. This may be of considerable advanta'ge in some cases inprev-entine" deterioration ofthe brushes or contact segmentsdue to sparks or arcing which may result if the Iii) connection is broken at this point. As soon as the restoring magnet 48 is energized as above described arm 42 will be moved to open position and all the signal circuits for that floor and direction of travel will be broken. The intcrcontrolling means will therefore be de-energized and all the contact arms 99 will be restored to closed position while the con.- tact arm 152 of the restoring circuit which has just operated will be restored to normal or open position by counter-weight 154.

The operator of car 1 may as before cancel the signals and transfer the same to the next car or to another car in the zone 111 but it will be seen that there is no need of a second car-operators transfer switch in the restoring circuit as in the form first described, since the opening of an established signal circuit for any car will automatically effect the opening of the connection between circuit closing members 152 and 151 in the corresponding restoring circuit, while the opening of transfer switch 111'by an operator before his signal circuits have been established, that is, in case he wishes to pass one or more floors without stopping, ensures that such connection between members 152 and 151 will remain open so that in either case operation of the restoring means by that car will be prevented. The elimination of the transfer switch in the car may be of advantage in some cases since it reduces the number of wires which must be connected to the car and may permit the use of a lighter cable for this purpose.

While the exact method of controlling the operation ofthe restoring means is somewhat,

different in the two forms of the invention, it is obvious that the result accomplished is substantially the same in any case, namely that when any car is in control of the signals for a certain floor all other cars are prevented from interfering with the signaling operation by operating the restoring means, while the controlling car is permitted to operate such restoring means upon passing out of the signaling zone. The means by which this is accomplished constitute in either case disabling means, since they disable the restoring circuits for all other cars from effecting the restoring operation. Such disabling means for each floor comprise, in the forms first described, the holding magnet 142 adapted to hold circuit closing arm 42 in closed position as long as any signal circuit remains established; in the second form such means comprise the circuit closing members 151 and 152, together with the electromagnet 105 controlling the same, said circuit-closing members being adapted to maintain an open break in all the restoring circuits except that corresponding to the signal circuit which is established. Other equivalent means might also be employed for this purpose, and my invention should therefore be understood to include the use of any such means by which this result ofselective control of the restoring means is accomplished. It will be seen that in both of the forms above described the armature portion 149 of each contact arm 42 and the corresponding restoring magnet such as 48 constitute restoring means adapted to movesaid contact arm so as to open the secondary circuit closer and thereby open all the signal circuits for that floor and direction of travel, and that means are also provided which are operable upon the establishing of any signal circuit to prevent effective operation of said restoring means by any restoring circuit corresponding to any other signal circuit.

lVhat I claim is 1. In an elevator signal system for a plurality of cars, a plurality of signal circuits corresponding to the respective cars, a single restoring means adapted to open all of said circuits, a plurality of restoring circuits corresponding to the respective cars and all connected to said single restoring means to control the same, a plurality of switching devices corresponding to the respective cars and operating in synchronism therewith to control the corresponding signal and restoring circuits, and disabling means included in part in said signal circuits and operable to prevent control of said restoring means by a restoring circuit corresponding to any car, while a signal circuit corresponding to any other car is completed.

2. In an elevator signal system for a plurality of cars, a plurality of signal circuits corresponding to the respective cars, a single normally open circuit closer included in all of said circuits, manually operable means for causing a movement of said circuit closer to its closed position, a single means for restorin said circuit closer to open position, a plurality of restoring circuits corresponding to the respective cars and all connected to said single restoring means to control the same, a plurality of switching devices corresponding to the respective cars and operating in synchronism therewith to control the corresponding signal and restoring circuits, and means included in said signal circuits for disabling any switching device from so controlling the restoring circuit while any other switching device is in control of its signal circuit.

3. In an elevator signal system for a plurality of cars, a plurality of signal circuits corresponding to the respective cars, a single restoring means adapted to open all of said circuits, a plurality of restoring circuits corresponding to the respective signal circuits and all connected to said single restoring means to control the same, a plurality of switching devices corresponding to the respective cars. and operating in synchronism therewith to control the respective erable upon completion of any one of said establish and break the corresponding signal 7 signal circuits to prevent control of said restoring means by a restoring circuit corre sponding to any other of said signal circuits.

4. In an elevator signal system, a construction as set forth in claim 3, each of said switching devices being adaptedto maintain closed connection in the corresponding restoring circuit at the time of opening the corresponding signal circuit, and thereby cause said restoringcircuit to control the restoring means.

5. In an elevator signal system for plurality of cars, a plurality of signal circuits corresponding to the respective cars, a single normally open circuit closer including in all of said circuits, means for closing said circuit closer, a single restoring means for restoring said circuit closer to open position, a plurality of restoring circuits corresponding to the respective signal circuits and all connected to said single restoring means to.

control the same, a plurality otswitching devices corresponding to the respective cars and operating in synchronism therewith to control the corresponding signal and restoring circuits,acircuit opening means included in the respective signal circuits and operable upon completion of a signal circuit corresponding to any one of said cars to prevent completion of a signal circuit corresponding to any other car, and normally inoperative disabling means included in said signal circuits and operable upon completion of said signal circuit corresponding, to one of said cars to prevent control of said restoring means by a'restoring circuit. corresponding to any other signal circuit.

6. In an'elevator signal system, a construction as set forth in 5, saic disabling means being adapted to'return to its normally inoperative condition upon subsequent opening of the completed signal: circuit, and said construction comprising in addition a manually controlled circuit opening switch in each of said signal circuits.

7. In an elevator signal system for a plurality of cars, a plurality of signal circuits corresponding to the respective cars, a single normally open circuit closer included in all of said signal circuits, means for closing. said circuit closer, a single electrically operated means'for restoring said circuit closer to open position, a plurality of restoring circuits corresponding to the respective cars and all connected to said single restoring means to controlfthe same, a plurality of switching devices corresponding to the respective cars and operating in synchromsmtherewith to and restoring circuits, and a' single electrically operated means included in all of said signal circuits and adapted, upon establishment of any one of said signal circuits, to hold said circuit closer in closedposition against the action of said restoring means.

8. In an elevator signal system, a construc tion as set forth in claim 7, each of said "switching devices being adapted tomaintain a closed connection in the corresponding restoring clrcuit at the time or" breaking the connection inthe corresponding signal cirresponding to the respective cars and connected to said restoring means to control the same, a plurality of switching devices corresponding to the respective cars and operating in synchronism therewith to control the corresponding signal and restoring circuits and thereby control the signaling and restoring operations, means included in said signal circuits for preventing any switching device from so'controlling the signaling operation while any other switching device is in control of the signaling operation, and other means included in said signal circuits for preventing any switching, device 'froinso controlling the restoring operation while such'other carcontrolled device is 111 control of the signaling operation;

' 10. In an elevator signal system for aplurality of cars vertically-movable to and from a plurality of landings, the combination of signals individual to each ofsaid cars,cir cuits for said si nals,switching devices connected to said circuits and operating in synchronism with the respective cars to cause operation of the signals corresponding to the respective carsas said cars approach one ofsaid landings at which a stop is desired and contributing to the restoration of any operated signal to inoperative condition as any car leaves said landing, and means included in said circults and operable to prevent the restoration of any operated signal by any car passing said landing unless such car is one whose switching device contributed to the operation of said signal;

' 11. In an elevator signal system for a plurality of cars vertically movable ,to-and from a plurality of landings, the combination of signals individual to each of said cars to indicate a landing which a stop is desired, circuits for said signals, means con- J i V 4 trolled from said landing for setting one ot said circuits in signaloperating condition,

switching devices connected to said circuits and operatingin synchronism with the respective cars to cause operation of the signal corresponding to respectlve cars in response ion to the operation of said signal setting means and contributing to the restoration of such signal setting means to inoperative condition as any car leaves said landing, and means included in said circuits operable to prevent the restoration of said signal setting means by any car passing said landing unless such car is one whose switching device contributed to the operation of said signal.

12. In an elevator signal system for a plurality of cars vertically movable to and from a plurality of landings, the combination of signals individual to each of said cars, cir cuits for said signals, switching devices operating in synchronism with the respective cars and defining signal zones for said landings, means controlled from said landings for setting said circuits in signal operating condition, means actuated by the switching device for the first car to enter a signal zone for a given landing after the operation of the signal setting means for such landing to cause operation of its individual signal, and contributing to the restoration of any opera-ted signal to inoperative condition as any car leaves said signal zone, and means to prevent effective operation of said signal restoring means with respect to said given landing by the switching device corresponding to any car passing said landing unless such car is one whose switching device contributed to the operation of the signal for said landing.

13. In an elevator signal system for a plurality of cars, the combination of individual signals for the respective cars, circuits for said signals, switching devices operating in synchronism with the respective cars and defining signal zones for the landings, means controlled from said landings for setting said circuits in signal operating condition, means actuated by the switching device for the first car to enter a signal zone for a given landing after the operation of the signal setting means for said landing to contribute to the operation of the signal for such car, and tending to cause restoration of the signal setting means for said given landing to inoperative condition as any car leaves the zone corresponding to said landing, and means to prevent eiiective operation of said signal restoring means by the switching device corresponding to any car passing said landing unless such car is one whose switching device contributed to the operation of the signal for said landing.

14. In an elevator signal system for a plurality of cars, signal circuits individual to each of said cars, a plurality of switching devices connected to said circuits and operating in synchronism with the respective cars to establish the corresponding circuits as the cars approach a landing, circuit opening means also included in said circuits and operative, in response to the operation of and operable to prevent efiective operation of said switching device actuated means by the switching device corresponding to any car while the signal circuit for any other car is established.

15; In an elevator signal system for a plurality of cars, signal circuits individual to each of said cars, a plurality of switching devices connected to said circuits and operating in synchronism with the respective cars to establish the corresponding circuits as the cars approach a landing, circuit opening means also included in said circuits and operative in response to the operation of any one of said switching devices to establish the corresponding signal circuits, to prevent establishment of the signal circuits for all the other cars for the same landing, means actuated by the switching devices for the respective cars and tending to open any established signal circuit as any car leaves said landing, and means included in said circuits and operable to prevent effective operation of said switching device actuated means while any signal circuit is established.

16. In an elevator signal system for a plurality of cars, the combination of stop signals individual to each of said cars to indicate a landing at which a stop is desired, circuits for said signals, means controlled from said landing for setting one of said circuits in signal operating condition, switching devices connected to said circuits, said switching devices being individual to each of said cars and each operating in synchronism with the associated car to cause subsequent operation of that cars signal in response to the operation of said signal setting means, said switching device tending to cause restoration of said signal setting means to inoperative condition as an car leaves said landing, and means incluc ed in said circuits and operable to prevent the restoration of said signal setting means by any car passing said landing unless such car is one whose switching device participated in the operation of said signal.

Signed at Los Angeles California, this 21st day of March 1925.

ROBERT H. GAYLORD. 

